val is_error : ('a, 'b) Result.t -> bool
val is_ok : ('a, 'b) Result.t -> bool
module Debug : 
functor (Stack : Stack_intf.S) -> Stack_intf.S with type t = 'a Stack.t
module Test : 
functor (Stack : Stack_intf.S) -> Stack_intf.S with type t = 'a Stack.t
include sig .. end